wordpress get_post_meta check if multiple values set

I've got a number of custom fields in a WP theme, and I want to check if they have values - but would like a short cut to check multiple values at once - something like this:

if ( get_post_meta ( $post->ID, "first_value", "second_value", "third_value", $single = true) !="") :

    // do stuff here, as they are all set ##

else:

    // do something else, as they are not all set ##

endif;

this does not throw an error, b开发者_高级运维ut it only checks if the first value is set - any ideas?

First note the affects of setting the $single variable to true:

If $single is set to false, or left blank, the function returns an array containing all values of the specified key. If $single is set to true, the function returns the first value of the specified key as a string, thus you can use string compare (not in an array)

Solution 1: That being said you could then use $single=false to get an array of values, and then compare the array of values to an array of null values.

Solution 2: Or you could use several conditions in the if_else statement:

if ( get_post_meta($post->ID,"first_value",true)!="" && get_post_meta($post->ID,"second_value",true)!="" && get_post_meta($post->ID,"third_value",true)!="") :

    // do stuff here, as they are all set ##

else:

    // do something else, as they are not all set ##

endif;

Solution 3: You could also use nested if_then statements if you prefer those.

The question is, which solution works best for you?